Manufacture of cans



April 2, 1963 A. STUCHBERY ETAL 1 8 5 MANUFACTURE OF CANS Filed June 12, 1959 s Sheets-Sheet 1 Fig.1.

PRIOR ART PRIOR ART Fly. 2.

PRIOR ART H 4. I PRIOR ART PRIOR ART In enter:

ART/4111a LESLIE TUCHBERY JosEF FRAME/ A ttorneys April 2, 1963 A. L. STUCHBERY ETAL 3,033,663

MANUFACTURE OF CANS Filed June 12, 1959 3 Sheets-Sheet 2 PRIOR ART Inventors ARTHUR issue Ewe/135M JoSEF FRHNEK April 2, 1963 A. L. STUCHBERY ETAL 3,083,653

MANUFACTURE OF CANS Filed June 12, 1959 3 Sheets-Sheet 3 "mentors ARTHUR [ESL/E Sn/c/wmy JosEF FRA/VEK I y E v 3,083,663 MANUFACTURE OF CANS Arthur Leslie Stuchbery, En'field, and Josef Franck, Willesden, London, England, assignors to The Metal Box Company Limited, London, Engiand, a British coinan p Filed June 12, 1959, Ser. No. 319,914 Claims priority, application Great Britain .iune 23, 1958 9 Ciaims. (UL 113-121) This invention relates to the manufacture of cans, for example cans the cross-section of which is circular, oval, or generally rectangular, and in particular to the securing of an end component to a can body.

As is Well understood the opposite ends of a can body usually have end components hermetically sealed thereto by seaming of the components to the body. For this purpose each end of the can body is provided with a continuous peripheral out-turned flange which is hooked into a continuous peripheral curl formed from the edge portion of a seam forming flange integral with the end component. The hermetic seal is formed by the application of lateral pressure to the hooked curls.

The creation of hermetic seals at the seams is of the essence of an acceptable can but heretofore the consistent formation of hermetic seals has been hindered by the formation of heavy, long pitch wrinkles during the first seaming operation resulting, after the second seaming operation, in the conditions known in the art as spurs, vees, puckers, and droop these being conditions in which there are localities in which the component curl is not properly engaged with the body flange. Investigation of these conditions, herein where convenient referred to collectively as imperfections, has shown that they are principally caused by the change in the peripheral length of the component during the turning over of the edge portion to form the curl thus resulting in the setting up of the above-mentioned wrinkles at widely separated, and usually at irregularly spaced, positions around the component.

It is a main object of the present invention so to prepare an end component for a seaming operation, or so to conduct a seaming operation, that when the component is seamed to a can body the tendency for the formation of imperfections is reduced to a minimum.

According to the present invention there is provided an end component for seaming to an end of a can body and which comprises a seam-forming flange an edge portion of which is formable as a continuous curl for cooperation with an out-turned flange formed at an end of a can body, characterised in that the flange is provided with undulations substantially evenly spaced therealong to accommodate changes in the peripheral length thereof during the seaming of the component to a can body for the purpose of reducing the tendency for imperfections as herein defined to be formed during the seaming operation.

Further, the invention provides the method of seaming an end component to a can body which consists of locating the seam-forming flange of an end component relative to an out-turned flange provided on a can body, overturning said flanges in known manner by a first and a second seaming operation to the seam, and before completion of the first seaming operation forming substantially evenly spaced undulations along the seam-forming flange of the end component to accommodate changes in the peripheral length of said seam-forming flange during the first seaming operation thereby to reduce the tendency for imperfections as herein defined to be formed during the seaming operation. The invention also con templates a can produced by the method just set forth.

3,083,653 Patented Apr. 2, 1963 In order that the invention may be clearly understood one embodiment thereof will now be described, by way of example, with reference to the accompanying diagrammatic drawings, in which:

FIGURE 1 illustrates the manner in which a flat seamforming flange is approached by the first-operation roll during a seaming operation,

FIGURE 2 illustrates the manner in which a curled seam-forming flange is approached by the first-operation roll during a seaming operation,

FIGURE 3 illustrates a method by which a curl is formed on the scam-forming flange of a can end component, and indicates a possible variation in [the length of the curl,

FIGURES 4 to 8 illustrate the manner in which imperfections are formed when using the previously known forms of end component,

FIGURE 9 illustrates a part of an end component according to the invention and which has a flat seam-forming flange,

FIGURE 10 is an underneath plan of an end component according to the invention, and in which the edge portion of the seam-forming flange is curled,

FIGURE 11 illustrates 'a part of FIGURE 10 to an enlarged scale,

FIGURES l2 and 13 illustrate steps in the forming of a seam using a component as illustrated in FIGURE 10, and

FIGURES 14 and 15 illustrate the manner of application of an end component to an end of a can body.

Like reference numerals refer to like parts throughout the figures of the drawings.

In FIGURE 1 there is illustrated a part of a circula tinplate can end component 1 as it has left the press and just as the seam-forming flange 2 is about to be engaged, in known manner, by a first-operation roll 3 the contour of which is adapted to perform the first seaming operation which includes the formation of a continuous peripheral curl 4 from the edge portion of seam-forming flange 2. FIGURE 2 illustrates a first seaming operation being performed on an end component the edge portion of the flange for which is pre-curled. As has been stated above the inturning of the curl during the first seaming operation changes the peripheral length of the component and sets up wrinkles 5, shown diagrammatically in FIGURE 5. A wrinkle is a somewhat wavelike deep discontinuity in the edge of the end component and is caused primarily by the compression action of the seaming profile of roll 3 during the seaming operation to a very slender section of the curl 4. This form of imperfection can be identified after the first seaming operation from a characteristic tight and polished spot 6, FIGURE 5, at the bottom of the curl 4.

FIGURES 3 and 4 illustrate a part of a can end component the curl for which is, as shown in full lines, partly formed by the press during the formation of the com ponent by the press. This results in the formation of variations in the length of the curl as indicated at 7. The curl 4 is completed by rollers, in known manner.

FIGURES 14 and 15 illustrate the manner of application of an end component to a can body 8 both for end components as known prior to the invention and as made according to the invention. As can be seen from FIGURE 14, the end of the can body is pnovided with an out-turned flange 9 about which the curl 4 is hooked. The curl 4- and flange 9 are intur-ned to the position shown in FIGURE 14, by first-operation seaming rolls 3 and second-operation seaming rolls, not shown, apply lateral pressure to compress them to form a seam as illustrated in FIGURE 15. When, however, the end component is of the kind known prior to the present invention the first seaming operation tends to create the irregularly spaced imperfections known as wrinkles as described above, and as the result of the formation of wrinkles there may, during the second seaming operation, be formed one or more of the imperfections known as a vee, a spur, a packer, or a droop. A vee, FIGURE 6, is caused by a heavy wrinkle 5 falling into a pleat which gives the appearance of a V-shaped notch as indicated in FIGURE 6. A droop 11, FIGURE 6 is a lowering of the bottom edge of the seam and is usually associated with the additional metal which occurs at the junction of the end seam with the side seam, not shown, of the can, although this condition can occur beneath a vee. A spur 12, FIGURE 7, is a very heavy vee, and a pucker "13, FIGURE 8, is caused by a wrinkle which, after the second seaming operation, falls into a pleat. The formation of any of these imperfections results in a nonhermetic seam.

FIGURES 9, 10 and 11 illustrate respectivelyan end component according to the invention in which a flat edge portion and a curled edge portion of the flange 2 is provided with undulations 14 which can be formed either during the stamping of the component by a press, or by tools which form the curl 4, either before or during the first seaming operation. The undulations are substantially evenly spaced along the curl 4 and have an 'mplitud'e and wave length which is predetermined to suit the particular manufacturing conditions and, as can be seen from FIG- URES 9, l0 and 11, the undulations are regular and relatively close one to the other. Each undulation is a wave formed by a very shallow deformation of the edge portion of the flange 2, see FIGURE 12, and is ironed out during the formation of the seam.

The end component is applied to a can body in the manner described above with reference to FIGURES 14 and 15, and during the first seaming operation the preformed undulations 14 remain uniform and slight as illustratedin FIGURE 12, the undulations accommodating the change in the peripheral length of the component during this operation. During the second stage seaming operation the small preformed undulations 9 tend to be ironed or flattened out to provide an even and uniform edge region for the flattened curl as illustrated in FIGURE 13, thus resulting in a hermetic seam which is free from imperfections as defined above.

If desired the undulations 14 may be formed by knurling,'stamping, extruding, embossing, or rolling prior to the first seaming operation, or the undulations may be formed during the first seaming operation.

As illustrated in FIGURES 9 to 13 the undulations are formed along the extreme edge of the edge portion of the flange 2 but, if desired, the undulations may be formed along the bend 15 of the curl 4. Further, if desired, a sealing compound may be incorporated in the seam as indicated at 16, FIGURE 15.

We claim:

1. An end component for seaming to .an end of a can body and which comprises a generally planar seamforming flange an'edge portion of which'is formable as a continuous curl for cooperation with an out-turned flange formed at an end of a can body, characterised in that the flange is provided with undulations substantially evenly spaced therealong to accommodate changes in the peripheral length thereof during the seaming of the component to a can body for the purpose of reducing the tendency for imperfections as herein defined to be formed during the seaming operation.

2. An end component according to claim 1, wherein the undulations are formed along the edge only of the flange.

3. The method of seaming an end component to a can body which consists of locating the seam-forming flange of an end component relative to an out-turned flange provided on a can body, over-turning said flanges in known manner by a first and a second seaming operation to the seam, and before completion of the first seaming operation forming closely and substantially evenly spaced undulations along the seam-forming flange of the end component to accommodate changes in the peripheral length of said seam-forming flange during the first seaming operation thereby to reduce the tendency for imperfections to be formed during the seaming operation.

4. The method according to claim 3, wherein the undulations are formed beforelocation of the end component relative to the can body.

5. The method according to claim 3, wherein the undulations are formed along the edge only of the seamform-ing flange of the end component.

6. The method of claim 3 wherein said undulations are ironed out during said second seaming operation.

7. An end component for seaming to an end of a can body comprising a can end defining portion and an integral outer flange, said flange being annular in outline and having an outer portion in the form of a continuous curl, and closely and evenly spaced undulations formed along the edge portion only of said flange to accommodate changes in the peripheral length of the edge portion of said flange during the seaming of said end component to a can body for the purpose of reducing the tendency for imperfections to beformed during a seammg operation.

8. An end component for seaming to an end of a can body and which comprises a generally planar seam-form,- ing flange an edge portion ofwhichis formable as a continuous curl for cooperation with an outturned flange formed at an end of a can body, characterized in that the flange is provided with undulations closely and substantially evenly spaced therealong to accommodate changes in'the peripheral length thereof during the seaming of the component to a can body for the purpose of reducing the tendency for imperfections as herein defined to be formed during the seaming operation;

9. An end component separate and apart from a can body and being adapted for seaming to an end of a can body comprising a can end defining portion and an in-, tegral outerflange, said flange being annular in outline and having an outer portion in" the form of a continuous curl, and evenly spaced undulations formed along the edge portion only of said flange to accommodate changes in the peripheral length of the edge portion of said flange during the seaming of said end component to a can body for the purpose of reducing the tendency for imperfections to be formed during a seaming operation.

References Cited in the file of this patent UNITED STATES PATENTS 700,578 Thompson u May 20, 1902 1,689,641 Pickles Oct. 30, 1 928 1,766,173 Hills June 24, 1930 1,929,339 Troyer Oct. 3, 1933 

1. AN END COMPONENT FOR SEAMING TO AN END OF A CAN BODY AND WHICH COMPRISES A GENERALLY PLANAR SEAMFORMING FLANGE AN EDGE PORTION OF WHICH IS FORMABLE AS A CONTINUOUS CURL FOR CO-OPERATION WITH AN OUT-TURNED FLANGE FORMED AT AN END OF A CAN BODY, CHARACTERISED IN THAT THE FLANGE IS PROVIDED WITH UNDULATIONS SUBSTANTIALLY EVENLY SPACED THEREALONG TO ACCOMMODATE CHANGES IN THE PERIPHERAL LENGTH THEREOF DURING THE SEAMING OF THE COMPONENT TO A CAN BODY FOR THE PURPOSE OF REDUCING THE TENDENCY FOR IMPERFECTIONS AS HEREIN DEFINED TO BE FORMED DURING THE SEAMING OPERATION. 